Reply to Cut length (phrase) of track ?

Hi guys,

For long time ago, I tried to find a method that can reduce number of phrases in a track in the smoothest way , but I still can't find it. For example a track contain 28 phrase (~7 min) to become a new track 20 phrase (~5 min). And it should be smooth so that audience can not realize the joint position.

Would you guys give me any suggestion?